Location-aware service discovery on IPv6 GeoNetworking for VANET Satoru Noguchi 1 , Manabu Tsukada 2 , Thierry Ernst 2 , Atsuo Inomata 1 , Kazutoshi Fujikawa 1 , 1 Nara Institute of Science and Technology, Japan 2 INRIA Rocquencourt/Mines ParisTech - CAOR Lab Wednesday, August 24, 2011
ITS application and services • Distributed application in Vehicles, Roadsides and Internet hosts integrated into ITS stations in vehicular communication systems • Composed of wide variety of services : • Software and/or Internet hardware entities Gateway providing a distinct Access Network Roadside ITS station Roadside ITS station capability ITS-S ITS-S ITS-S Router (AR) Router (AR) hosts ITS-S ITS-S ITS-S ITS-S Router (MR) hosts hosts Router (MR) Vehicle ITS station Vehicle ITS station VANET 2 Wednesday, August 24, 2011
Service Discovery Protocol (SDP) • ITS applications need to orchestrate multiple services remotely • IP routing has already been deployed, but available/ appropriate services for a particular user are variable • Depending on time, driving condition, geographic location... • SDP dynamically discovers available services • SDP: Locate communication endpoints (i.e. socket) of services with application specific criteria • IP routing: If a node knows destination’s IP address, it can access necessary services 3 Wednesday, August 24, 2011
Requirements for ITS SDP in VANET 1. Geographical location aware: discover services according to geographical location • ITS-related services are highly dependent on geographical location 2. Low latency discovery (i.e. from 10ms to 1000ms) • For critical use cases 3. Low bandwidth usage • i.e. For highly-congested intersections 4 Wednesday, August 24, 2011
IPv6 GeoNetworking • Adaptation of IPv6 to C2CNet layer : supports geographical addressing and routing by means of encapsulating IPv6 packet with a C2CNet header • C2CNet header contains source and destination C2CNet identifier, source and destination geographic position • By nature C2CNet layer exchanges packets without IP • EU project GeoNet defined how to transmit IPv6 packets over C2CNet; “ IPv6 over C2CNet ” • Reference specification has been published by GeoNet 5 Wednesday, August 24, 2011
Geographical routing • Deliver IPv6 packets to all nodes inside a particular geographical area (GeoDestination) • i.e. A particular IPv6 address can be used as a GeoDestination; FF0E::1 -> a 500m radius centred from sender (GeoBroadcast) • Upper layers can transparently use Geographical routing via regular IPv6 API GeoDestination r GeoBroadcast 6 Wednesday, August 24, 2011
Service location protocol version2 (SLPv2) with IPv6 modification • Standardized by IETF; RFC2608, 3111 • Discover services using IPv6 multicast • One multicast address for one service (Address range: FF0x::1:1000 - FF0x::1:13FF ) • Support centralized/distributed discovery with/without Directory Agent • Pros: reduce unnecessary messages; deliver service discovery messages to a specific subset of nodes 7 Wednesday, August 24, 2011
Multicast-baed service discovery on IPv6 GeoNetworking • Service discovery protocol: SLPv2 with IPv6 modification • Multicast request / Unicast reply • VANET routing: IPv6 GeoNetworking • SDP Components: Service Consumer (SC), Service Provider (SP) Hosts Hosts Application Service SC/SP SC/SP TCP UDP TCP UDP MR/AR MR/AR Intermediate MR/AR IPv6 IPv6 IPv6 IPv6 C2CNet C2CNet C2CNet GPS GPS GPS PHY/MAC PHY/MAC PHY/MAC PHY/MAC PHY/MAC Station-internal network (e.g. Ethernet) 8 Wireless access technologies(e.g. WLAN) Wednesday, August 24, 2011
SDP Packet encapsulation 1. SC sends a service discovery request message (SrvRqst in SLP) through IPv6 multicast 2. Sender router encapsulates IPv6 multicast packet (SrvRqst) into GeoBroadcast packet and deliver corresponding destination 3. Receiver router decapsulate GeoBroadcast packet into IPv6 multicast packet and deliver it to SR Regular IPv6 IPv6 over C2CNet Regular IPv6 Multicast SrvRqst Multicast SrvRqst GeoBroadcast Dst: FF05::1:1000/118 Dst: FF05::1:1000/118 Hosts (SC) MR/AR MR/AR Hosts (SP) Unicast SrvRply Unicast SrvRply GeoUnicast 9 Dst: SC Dst: SC Wednesday, August 24, 2011
Message sequence Hosts MR/AR (IPv6 MR/AR (IPv6 Hosts (SC) GeoNetworking) GeoNetworking) (SP) Service MLD_report acvivation request Add_mapping from application SrvRqst (multicast) GeoBroadcast SrvRqst (multicast) SrvRply (Unicast) Service LS request discovery LS reply GeoUnicast SrvRply (Unicast) Service Data request/reply operation 10 Wednesday, August 24, 2011
IPv6 multicast over GeoBroadcast Network layer IPv6 multicast group member C2CNet layer GeoDestination SP (Non-requested service) SP (Requested service) SC 11 Wednesday, August 24, 2011
Implementation • OS: Linux (Ubuntu 10.11, kernel 2.6.35 with IPv6 multicast forwarding support) • SDP components: OpenSLP beta1 • IPv6 GeoNetworking: CarGeo6 v0.9.8.1 • Open implementation of IPv6 GeoNetworking reference specification by CarGeo6 Project • IPv6 Multicast forwarding daemon (ingress <-> egress IF on router) • gpsd-2.96 http://www.cargeo6.org/ 12 Wednesday, August 24, 2011
Implementation (cont.) IPv6 GeoNetworking enabled router GPS C2CNet IPv6 Payload Position Geo-routing sensor (gpsd) G e o - M u l t i c a s t D e s t i n a t i o n f o r w a r d i n g CarGeo6 IPv6 Payload Userland routing raw icmpv6 tun0 socket socket Kernel mr_cache m r o u t e 6 Routing IP lter table mr_vif e t h 0 w l a n 0 Mac IPv6 Payload Mac C2CNet IPv6 Payload Host Application SC/SP /Service 13 Wednesday, August 24, 2011
Evaluation • Field evaluation at NAIST (jp) • 3 sets of ITS station (MR and Host) • 1 moving station (SC: Host1 and MR1), and 2 parking stations (SP1, SP2) • WLAN (802.11 b/g) • Duration: 720min 14 Wednesday, August 24, 2011
Evaluation Results • End-to-end latency (min/max/average, ms) • 1 hop: 3.59 / 23.3 / 7.86 • 2 hops: 27.9 / 170 / 48.6 Message Overhead (in 720sec) 600 GeoBroadCast GeoUnicast • Message overhead LS 500 Beacon Transmitted pakets (Kbyte) • 0.73kb/sec total 400 300 • Success late 200 • 1hop: 75%, 2hops: 52% 100 0 SC SP1(1hop) SP2(2hop) Total 15 Wednesday, August 24, 2011
Visualization with AnaVANET 16 Wednesday, August 24, 2011
Conclusion • Multicast service discovery on IPv6 GeoNetworking for VANET • Based on GeoBroadcast and IPv6 multicast • Low latency, Low bandwidth usage, geographical location aware service discovery mechanism • Actual implementation on Linux PC and field evaluation • Future work • Improve success late: • IPv6 GeoNetworking Multi-hop handling of CarGeo6 • Service discovery Timeout and Retry count configuration • Wide area service discovery via Internet 17 Wednesday, August 24, 2011
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